Machine for turning irregular forms



F. S. BUCK.

MACHLNE FOR TURNING IRREGULAR FORMS. APPLICATION FILED APR. 1,0, 19.15- RENEWED OCT. 25. 1918.

1,330,841. Patented Feb. 111920.. in 4 SHEETS-Sl 1- H Y v l L 45 F. s. BUCK. MACHINE FOR TURNING IRREGULAR FORMS.

APPLICATION FILED APR. I0. 1915. RENEWED OCT. 25. I9I8.

Patented Feb. 17, 1920.

4 SHEETS-SHEET 2.

lh. S. BUCK. MACHINE FOR URNING IHREGULAR FORMS. APPLICATION FILED APR. Io, I9I5. RENEwED ocT. 25. Isla.

Patented Feb. 17,1920.

4 SHEETS-SHEET 3 F. S. BUCK.

MACHINE FOR TUNNING mNEeuL/N FORMS. l APPLICTION FILED APR. 10| 1915. RENEWED OCT. 25,1918.

1,330,841 U Patented Feb, 17, 1920.

4 SHEETS-SHEET 4.

' STATES PATENT OFFICE. ERANx s Buen,y or sPRrNcrIELD, VERMONT, AssIGNoR, BY MESNE ASSIGNMENTS, To EITz-EMPIRE nou-BEE PIvoT LAST oo., or ROCHESTER, NEW YORK, A coRroRATroN or MAINE.

MACHINE FOR TURNING IRRGULAR FOMS.

speeiacation of Letters Patent. Patented Feb. 17, 1920. l,

kApplicaticn led April 10, 1915, Serial No. 20,432. Renewed October 25, 1918. Serial No. 259,716.

To all whom t may concern.'

Be it known that I, FRANK S. BUCK, a citizen of the United States, and residentv of Springfield, in thecounty of Windsor and State of Vermont, have invented Certain new;y

and useful Improvements in Machines for Turning Irregular Forms, of which the fol lowing isa, specification.

The present invention 'relates to machines lfor turning irregular forms and particularly to machines for cutting lasts. It is peculiarly adapted for successful operation according to the principles discsed in Patent No. 1,137,117, granted April 27, 1915.

Prior to my invention set forth in the said patent, one great difficulty experienced in cutting lasts was the absolute failure of the machine to reproduce the more sharply concaved portions of lasts of many styles, due to the. comparative Illatness of the large model wheel which had to be used on these machines. This necessitated digging out these concavities in a. further expensive and inaccurate operation.

My invention disclosed inl said Patent No. l1,137 .117 placed the cutter'axisat an acute angle with the work axis in the direc-- tion of feed of the cutter and thereby secured the. advantages of a small model wheel and cutter head with consequent accuracy in reproduction which had been unattainable with parallel work and cutter axes; an arrange-ment of the rolighing and finishing cutters along and close to the angledaxis which broughtl the cutting edges into ,more efficienty working relation with the block than p had been possible with prior types and, at

the same time, secured compactness which had been, until then, unattained in a. practical 'last lathe cutter head; and avoided, among others, ditliculties incident to compressive and bending stresses in the cutterl shaft, to the catching or ,hogg1ng of the.

cutter into the work, 'and to the boring (as distinct from shaving) action of the cutter head which had arisen in connection with attempts to incline the direction.

The angle between the cutter axis and the i work axis in the machine shown in the patj ent referred to was about-.eighty degrees.l I

have found by subsequent experimentation that the advantages ofmy prior invention are ,secured ,to n much greater extent by an 'axis in the wrongA yangle of less than forty-five degrees, and

that other advantages of great importance result from such a sharply acute angle.

The more acute angle has increased the advantages secured by my `former invenabsence of the gouging or hogging eectl met with where a cutting tool is pointed into the work, and is still ample to secure clearance between the work and the cutter arbor and its supporting mechanism, while permitting the use of a model wheel and cutter assmall as three inches in diameter. Secondly, such a sharply acute angle also permits a radial reorganization of the type of cutter head used. A finishing cutter head on a shaft far from parallelism with the axis of the work must necessarily be substantially spherical, if itis toy reproduce the concavities of the model properly. Cutter heads of the spheroidal type are expensive, diliicult to grind, repair and adjust, and are not as clean cutting as the type about to be mentioned. p

An axis at a considerable distance from the perpendicular to the work axis permits the use of a flat disk-shaped finishing cutter head of convenient size for economic construction and operation, and of proper effective contour for accurate reproduction of the model. This type of cutter head had never before beeninco'rporated in a prac tical small cutter head machine. Such a cutter head on an inclined axis has been suggested before, but the axis was inclined in the wrong direc-tion, and consequently the machines in question were subject to various serious disadvantages such as digging into the work, an expensive and cumbersome plural shaft construction, etc., in the effort to avoid which the cutter axis was swung toward the perpendicular by other experimenters, who thereupon sacrificed the advantage of the disk form of cutter head. The invention of said Patent No. 1,137.117 swung the axis beyond the perpendicular,

.but the additional sharpening of the angle tlisk type, with all its practical advantages,

While retaining andy increasing the advan,

v permits the production of high coned lasts tages of the invention of the previous patenti Another distinct advantage resulting from the more acute angle of the present inven- -tion arises in connection with the turning of modern high coned lasts. These lasts rise sharply and for a considerable distance from the fiat top of the cone to the top of the instep, thus forming a last' with a long extended instep, or so-called high -cone. Itis impossible to cut a sharp lateral projection on a lastwith a cutter head of the disk type on an axis` near the perpendicular f to that of the Work. I have found that the sharply acute angle of my present invention of the most extreme styles desired.

Accordingly I regard a cutter Vshaft in-l clined toward the direction of feed at an angle of less' than 15 witli the axis of the work as, an important feature of my invention.

Another important advantage of the invention proceeds from the shape of the cutter head itself. The cutter head of the pres- 'ent invention is conical or pear-shaped with the large end toward the axis of the work.

lThis construction has several advantages.

' It stiifens and supports the necessarily projectingv end of the cutter arbor, distributes the cutting action'along it and enables the removal of the wood in thinnerl chips with less vibration and bending moment 1n the l arbor. With they axis inclined as described, the finishing blades are at the large end of the cutter head and are therefore vgiven a vrapid velocity, as is necessary for smooth work, while the roughing blades, which have the heaviest work to do, but which are not required to do it smoothly -nor tolmove at high speed, are close to the axis and therefore supported firmly and simply.` This construction, moreover, has an. important bearingon the matter of cutting high coned lasts, already mentioned, The conical or I l portions.

The improvements in which the' present invention consists may be applied to and used inconnectionl with any lathe adapted to turn irregularwork, and in the following specification and the drawings forming' a part of the same are described and shown as applied to a last lathe of standard pattern, without however implying anfintention to restrict the scope of the vpresent invention to that or any other particular turning. lathe. In the drawings, l i

Figure l represents in front elevation a work and the model, respecti ely.

fthe work model guide, and indicating the relation e' which the cutter and guide occupy tothe Fig.. 4 is a plan view of the Q guide pulley which forms p a part of the drive for the cutter.

Fig. .5 is a projection of Fig. 4, 1n the directionof the arrow.

Fig. 6 is a side elevation of my improved cutter head.

Fig. 7 is an end elevation Vof the cutter head with the finishing cutter removed.

Fig. 8 is an end elevation partly in section of the finishing cutter shownV in Fig. 6.

Fig. 9 is a side elevation andl Fig. 10 an end view of another form of y cutter head and cuttersembodying the general principles but indifferent form of the cutter head and cutters shown in Figs: 6, 7, and 8.

The same reference characters indicate the same arts in all the figures. J

Re erring to Figs: 1, 2,and 3 11 represents the bed of a last-lathe of 'standard form which is supportedupon legs 12 and has an overhanging frame 13-13 on which a swing 14 141` is hung.by means of the pivot rod 15. 'The swing is provided. with the usual centers 16 and 17 for the model 18, the centers 19 and 20 for the work or block 21 and the supportingdriving and adjustingy means for Such centers, which,

forming no part of the present invention require no description.

The bed hasv guideways 22," 23, and .24l on which rest the 'carriage 25 for the model Aguide qand thev carriage 26 forl the' cutter spindle, such carriages being movable in unison along the guideways in 'directions generally'parallel to th axes ofrotation of the modeland of the 'work piece, and being so moved at the same speed orat different speedsy by any usual or other suitable for. the purpose. y

Standards 27 and 28 on the cutter spindle carriage have bearings inwhich the cutter spindle 29 is rotatably mounted, said bearings being arranged to hld the spindle at mechanisms an acute angle to the axis of rotation of the work and preferably, though not necessarily l in the same horizontal plane with the axis of rotation of the work. 30 representsthe cutter head onthe end ofthe spindle nearest i In'the apparatus shown, the 'cutter spindle .l is rotated at a highrate of speed from a i drum .31 on thefmainshaft 32 by a belt which passes underthe drum'. and overa pulley 33 on thespindleand between guide pulleys 34 l1'30 adjustable 775 vley 35 tocause lthe belt to run true over the spindle pulley 33 without Vworking over either end thereof. Pulley 34 is mounted on a xed stud 36 secured to the under side of the cutter carriage on an axis parallel, or approximately so, to the axis of the drum. Pulley 35 is mounted on a pivot stud 37 secured in a head 38 which is adjustably connected to a bracket 39 by means of a bolt 40 passing through a iiange 41 on the bracket,

and the bracket is adjustably angularly connected to the under side of the carriage by a. bolt 42. Bolt 42 is vertical, and bolt 40 is horizontal, `and is also perpendicular to the bolt 42. The bracket and the pulley can be adjusted angularly about the bolt 41 and the pulley can be further adjusted angularly with respect to the bracketv about bolt 40. This gives capacity for adjustment of the pulley in two directions and enables it to be so placed that the belt will run properly between the drum and the cutter spindle pulley. v

The model guide 43 is a disk substantially v equivalent in size to the surface of revolution generated by the finishing cutter of the cutter head and is rotatably mounted on an axis parellel to that of thel cutter spindle and mounted on a bar 45. The bar 45 is horizontally adjustable, forward or back, on the Width grading slide 44', which is mounted slidably on the standard44 of the model wheel carriage, as is well understood by workers in this art.

The preferred form of my novel cutter head is shown in detail in Figs. 6, 7, and 8. It comprises three roughing cutters 46, 47, and 48 and a finishing cutter 49, all mounted on the spindle 29. The roughing cutters are substantially alike except for differences of diameter and a variation in external form of the cutter 48. Each consists of a collar or hub 50 which lits the spindle and is in close abutting terminal Contact with the adjacent hubs and is provided with a keyway to receive a spline or key 5l on the spindle, and has a number of arms 52, each provided with a lip 53 sharpened at one edge 54 to act as a knife. The arms are at one end of the hub and the sharpened lips extend toward of the lip so that such cutting edge crosses the arm 'as well as extends beside the same.

.Preferably thevouter surfaces of the knife lips and the knife edges are elements of a conical surface of which the larger diameter is toward the end of the spindle. The three cutters 46, 47 and 48 have generally similar surfaces of gradually increasing diameter so that collectively the surface of revolution described by their cutting edges is approximately a continuous cone. While I have shown three roughing cutters I have not intended thereby to limit the invention to a cutter head having neither more nor r`less than three cutters. The finishing cutter is on the extreme end of the spindle, that is at the base of the cutter head, and is the nearest of all the cutters to the axis of the work, as well as being the most remote of the cutters from the axis of the spindle. It is formed with arms each of which is provided With a transverse aperture 55 which is enlarged at one side of the arm to .form a cutting edge 56. Such cutting edge 1s vreinforced and supported by the material at each end of thefcutter, instead of being supported only at one end, asis the case with the other cutters.

In the cutter head shown in Figs. 9 and l0 there are three cutters 57, 58, and 59 which are preferably employed as roughing cutters in connection with a finishing cutter such as the cutter 49; although if desired the cutters 57 and 58 may be employed for roughing and the cutter 59 for finishing. In the construction shown these cutters are Substantially like the cut-ters 46, 47 and 48 with this exception that the cutting edges and the lips or webs on which said cutting edges are' formed are curved longitudinally instead of being substantially straight. If desired the three cutters shown in Fig. 9 may be employed as roughing cutters in connection with a finishing cutter which may be the same as the finishing cutter 49. The pear or bell-shaped form of the cutter shown in Fig. 9 is somewhat more accentuated than is that shown in F ig. 6, the cutter 59 projecting relatively farther beyond the surface generated by the other cutters than the cutter 56. This form permits the finishing cutter to drop to the ball while the roughing cutter is working on: the upper part of the' instep, with a greater inclination of the axis than would be possible if f the generating l-ineof the lateral conical surface of the cutter were exactly straight. The .advantage of such structure in the lcutting of high coned lasts has already lbeen suggested.

The finishing cutter has the same outer diameter as the guide Wheel 43 and its edge is curved on the same radius as the ,transverse curvature of the rim of such wheel, whereby the surfaces formed by the finishing cutter may conform exactly to the surfaces on the model on which the guide acts, except for such differences as are caused by rotating the work in reverse direction to the model. This is because the effective curvamodel, and by length and width grading.` The angle between the cutter axis and the axis of the work is considerably less than 45. In the machine shown it is about 30. I have found after a great deal of experimentation that this angle greatly increases the advantages of my prior invention above discussed as compared with the machine disclosed in saidearlier atent in which the angle was about 80. hev advantage of the draw cut is very much accentuated. It is necessary to incline the cutter axis of a small cutter head in order to carry out of the way of the work the bearings and the arbor which have to be rather rugged to perform properly the heavy work they have to do. The diiiculties inherent in machines previously suggested, in which the cutter axis was inclined in the wrong direction (among others, excessive vibration of the cutter arbor due to compressive stresses, and a tendency to catch and dig into the work) have been avoided by inclining the cutter axis forward instead of backward, as in the machine of the prior patent, and the'axis is brought much more nearly parallel to that.

of the work than ,in my prior machine so that vthere is far less bending moment on thel arbor with correspondingly less vibration and chatter. At the same time, the angle is ample to secure clearance between the work and the cutter head supporting mechanism.

Further, the new angle results in the production 0f smoother work than was possible at the v80 degree angle. There are many places on a last where the wood fibers run out into the surface. A blade on an axis too far from parallelism with the-fibers will cut directly against the, grain on some of these parts and cause roughness in the surface cut. Also, the tip of the cutter has small peripheral velocity and consequently cuts less freely than other parts of the cutter. T hese difficulties are avoided bythe new angle between the cutter and work axes. The two axes are near enough to parallelism to avoid any appreciable effects of cutting againstl the grain, and the blades of the cutter head are all placeable farv from the dead point.

The change in the angle which characterizes lthe present invention also. secured, among others, several further very important advantages not obtainable with the machine of the patent. Almodel wheel the axis of which is near the perpendicular to that of the work must benearly or quite spherical in order to enterthe concavities of the ture of a disk-shaped model wheel is the curvature of its projection on a plane perpendicular to the axis of the work. This will be much flatter than the curvature of a principal section of the wheel perpendicular to its axis of rotation if such axis makes a large angle with that of the work. A cutter head of the spheroidal form is expensive to construct and to kee in order. The blades of a last lathe cutter head should be easilyremovable for grinding, and easily adjustable and interchangeable, and these objects are very diflicult -of attainment fwith a spheroidal cutter head. The inclining of the axis below 45 enables me to use a diskshaped model wheel with a nishing cutter of corresponding shape. Such an instrumentality is of a radically dierent type and is much easier to construct in a practical manner and to keep in order.

A further advantage was found in the superior capabilities of the new machine in cutting so-called high coned lasts. In lasts of this type the instep ridge-runs up to a point considerably higher than its usual point of termination and then descends sharply to the fiat top of the cone. A cutter head which is inclined far from the workV axisv cannot cut such a last because after the front of the projection has been cut the model wheel will hang up on it and'prevent thecutter from working down the rear side of the projection. yThe new angle enables the machine to cut lasts with much higher, sharper cones than theJ old.

The cutter head itself, by virtue of its shape, possesses several advantages ver the substantially cylindrical form shown in said previous patent.- It. is conical or pear shaped, with the large end toward the work. The general line of the` cutting edges is thus arranged roughly parallel with the ridge of the instep. This structure has, among others, the following advantages. The finishing blades are at the'large end and arel consequently given a greater linear velocity than the roughing blades which, in their turn, are closer to the axis and can be fastened securely and rigidly. I t is not necessary that the roughing blades move so rapidly asthe front blades since they are not obliged to do smooth work while it is necessar that they be lstrong and durable.

econdly, it is necessary that the cutter axis project several inches toward the work, beyond its bearing, inorder to insure that iio :the block will not strike the necessarily large and substantial bearing as it rotates. The roughing and finishing cutters are ar.-

ranged side by side injorder with their hubs ofthe same amount of material per second in thinner chips than would otherwise be the case, and with a consequently smaller expenditure of power and less vibration.

Y At the"lsame time the conical shape of the cutter head, when the cutters are arranged `as above explained, tips the axis to a more acute angle with the axis of the work than would be possible if the cutter head were `cylindrical or conical with its small end t0- ward the work, and this facilitates the cutting of high coned lasts. x

.This additional acuteness of the angle of the shaft also enhances the advantage already discussed relatiye to the drawing of the cutter over the work bytensile rather than compressive action of the cutter shaft with the consequent creation of minimum bending (stresses in it, and diminution of the liability to .dig7 into the work. rPhere is of, course a limit to the extent to which the line of cutting edges can be inclined-determined by the condition of things at the timethe roughing cutter is working onthe upper part of the instep and the finisher is treating the top of the ball.. It is advan tageous to run the cutter shaft at a more Yacute angle than that made by Vthe instep ridge with` the work axis, and the conical cutter head permits this. Angling theL shaft too much toward the axis would bring it too near parallelism` so that the small cutter hea`d could not be used. I have found that an angle of about 30 is close enough' to parallelism to secure advantageous action of the shaft and at the same time is far enough from parallelismto secure the advantages of the small model wheel and cutter and of` the com act high speed cutter head.

The ormation and arrangement of the cutters not only provides a combined great length of cutting edge, but also provides what is in effect a plurality of such cutting edges and divides each edge into a number of segments which are disposed out of alinement so as to bring them into action successively and distribute the cuttingV effort; while at the same time providing ample spaces between the adjacent blades, Aand between the blades and hubs of the roughing cutters, and through the arms of the finishing cutter, for escape of chips. If a greater or less eective length of cutting edge is required, additional cutters may readily be placed on the spindle, or one vor more of the cutters rshown may, be as easily removed. The cutter instrument thus` has great iexibility for expansion and contraction without modifying its other characteristics.

In explanation of the terms'employed 1n this description and in the following claims, I would say that each of the cutters maybe called a cutting` unit, having any desired number of blades, thel cutting edge of each blade constitutes a segment or Izone-of the collective cutting edge which is provided by the contiguous blades of respectively adjacent cutters. yThe -entirecollection of cutting units constitutes the complete cutter instrument. L

What I vclaim and desire ters Patent is l. A machine for turning irregulan forms comprising a rotatable work holder, a cutter holder, one of said holders being movable relatively to the other in a line parallel to the axis of rotation of said work holder, and a cutter of generally conical form tion mounted on said cutter holder to turn a out an axis extending at an acute angle to the axis of rotation of the work holder in the to secure by Letdirection `'of progressive cutting action, and v being further arranged with its base nearest cutting action and having an end projecting in proximity to the work, and a cutter instrument* mounted on said projecting end having an advance rough cutting portion and a following finishingl portion, said p0rtions arranged to travel in a surface of revolution which is approximately conical and arranged with that part which forms the base of the cone nearest to the axis of the work. s

3. A machine for turning irregular forms comprising the combination of work holding means adapted to support and rotate a work piece, a cutter holder mounted to travel in a direction approximately parallel to the axis of rotation of the work, a cutter spindle carried by said cutter holder projecting therefrom toward the axis of the work, the angle between said spindle and axis in the direction of cutting feed being acute, and a cutter instrument mounted on .said cutter s indle adjacent to the rojecting end thereo and comprising roug cutting and finishing portions; the rough, cutting portion being in advance of the finishing portion and being also nearer to the spindle than the latter, whereb theline between the surfaces of revolution of said portions at thel side thereadapted to sup- 1 tingaction in a direction approximately parallel to`the axis of rotation of the work, a cutter spindle mounted in said cutter holder making an acute angle with the axis of the work in the direction of progressive cutting action and having an end projecting in proximity to the werk, and a cutter instrument mounted onfsaid projecting end having an- 'advance rough cutting portion and a following finishingportion, said prtions arranged to travel in; a surface of revolution which` is approximately pear-shaped and arranged with that part which forms l A the thick part of the pea-r nearest to the axis of the work. v

5.y A machine ofthe cl-ass described comprising a work holder adapted to,j support i vand rotate a work piece, a cutter holder, one

-from the work piece.

of said holders being movable relatively to the other to cause a progressive cutting action in a ,direction approximately parallel to the axis of rotation of the work, and a cutter spindle mounted in said cutter holder 'making an angle of substantially less than with the axis of the work in the direction of progressive'cutting action.

6'. A machine of the class described comprising a work holder adapted to support and rotatev a work piece, a cutter holder, one of said holders being movable relativelyto the other to cause a. progressive cutting action in a direction approximately parallel to the axis of rotation of the work and a cutterspindle mounted in said cutter holder in a position of approximate parallelism with lan adjacent instep 4ridge of a last being cut 7. A machine of the class described" comprising a work holder adapted to support and rotate a work piece, a cutter holder, one of said holders being movable relatively to the other to cause a progressive cutting action in a direction approximately parallel to the axis of rotation of the work, .a cutter spindle mounted in said cutter holder.- mak? ing an angle of substantially less than 45 end projecting 1n lproximity to the work, andY with the axis of the work lin the direction of progresslve cutting action and having an a cutter instrument mounted on said projecting end having an advance rough cuttingportion anda following finishing portion, said portions arranged to travel in a surface of'revolution which is approximately pear-shaped and arranged with that part which forms the thick part of the pear nearest to the axis of the work.

8. A machine of the class described comprising a work holder adapted to support and rotate a work piece, a cutter holder, one of said lholders being movable relatively to the other to cause a progressive cutting ac-4 tion in a direction approximately parallel to the axis of rotation of the work, a cutter:

spindle mounted in said cutter holder in a from the work piece and having an end proj ecting in proxlmity to the work, and a cutter instrument mounted on said projecting end having an advance rough cutting portion and a following finishing portion, said portions arranged to travel in a surface of '65 position of approximate parallelism fwith an adjacent instep ridge of a last being cut revolution which, is approximately pearf shaped and arranged with that part which forms the thick part of the pear nearest to the axis of the work.

9. In a machine of the class described, a work holder and` a cutter holder arranged for relative traverse to ee'ct progressive cutting action on the work, a cutter instrumentality mounted on the cutter holder with its axis inclined acutely toward the direction of relative cutting feed at an angle substantially less than 450, and a disk-shaped model wheel arranged on a similarly arranged axis,

having a diameter not substantially greater than the thickness of the largest model used Vin practice, the cutter instrumentality hav'- ing a finishing portion of corresponding shape. Y

l0.' A machine of the class described comprising a work holder adapted to support and rotate a work piece, a cutter holder, one of said holders being movable relatively to the other to cause ay progr sive cutting action in a direction approximately parallel to signature. FRANK S. BUCK.

Coreetion in Letters Patent NOQQSSUQSM.

.Signed end sealed 6th day of Ju1y,A. D., 1920.V

It is hereby certified that in Letters Ptent N o. 1,330,8441, granted February 17? A'1920,vup'on theepplioationof Fre-nk S. vuok, of Springfield, Vermont., for en Y I' y improvement in Machines for Turmug Irregular Forms, an error appears 1n the printed specification requiring Correction as`fo11owsz- Page line 120, elain, for i the `Words line between reed general direction of the Zine joining; and that the seid Letters Ptent should/ be read with this correction thereiri that the same may confform to the record of the case in the Patent Oioe.

Acting ommissioner of Paenis. 

